“It sounds like you have a difficult decision to make.”

Your best friend has been offered her dream job. But if she takes the job, she will have to move to a new city and break up with her boyfriend. She tells you about this situation. You say this to express to her that you understand how hard this choice must be.

This means that a person has to decide something. This phrase is usually used when talking about big decisions with important consequences. You wouldn't use this phrase to talk about deciding which movie to watch, for example, unless you were saying it as a joke.